FSH-releasing peptides

ABSTRACT

Lamprey LHRH-III is a potent FSH-releasing factor, and may be used to enhance fertility. Antagonists to lamprey LHRH-III may be used to inhibit fertility.

[0001] The benefit of the Jun. 4, 1997 filing date of provisionalapplication serial No. 60/091,112 (which was a conversion ofnonprovisional application Ser. No. 08/869,153) is claimed under 35U.S.C. §119(e) in the United States. The benefit of the Jun. 4, 1997filing date of application Ser. No. 08/869,153 is claimed underapplicable treaties and conventions outside the United States.

[0002] This invention was made with support from the United StatesGovernment under Grants DK43900 and MH51853 awarded by the NationalInstitutes of Health. The United States Government has certain rights inthis invention.

TECHNICAL FIELD

[0003] This invention pertains to compositions and methods forselectively stimulating or inhibiting the release offollicle-stimulating hormone from the anterior lobe of the pituitarygland.

BACKGROUND ART

[0004] The brain controls the release of gonadotropin hormones from theanterior pituitary gland. Two important gonadotropins arefollicle-stimulating hormone (FSH) and luteinizing hormone (LH). FSH iscritical for spermatogenesis and for ovarian follicle development, whileLH is critical to androgen secretion in males, and estrogen secretion,ovulation, and formation of the corpus luteum in females. A hormone withspecific activity for releasing FSH but not LH could be used to increasefertility in humans or other animals, or to correct fertility problemscaused by defective hypothalamic control of FSH secretion. Conversely,antisera or other antagonists to an FSH-specific releasing factor willinhibit FSH secretion, thereby inhibiting spermatogenesis in males, orinhibiting development of follicles and ovarian development in females,providing a new antifertility drug. It is also possible that very highdoses of an FSH-specific releasing factor will inhibit FSH secretion,rather than stimulate it.

[0005] Prior indirect evidence has suggested that separate factors couldbe responsible for triggering the release of FSH and for triggering therelease of LH in mammals. However, this hypothesis could not previouslybe confirmed, because no previous work successfully isolated a potentfactor that selectively induces the release of FSH, but not LH. SeeMcCann, S. et al., Control of follicle-stimulating hormone andluteinizing hormone release by hypothalamic peptides, Annals New YorkAcademy of Sciences, 687:55-59, 1993; Dees, W. et al., Ethanol and thepulsatile release of luteinizing hormone, follicle stimulating hormoneand prolactin in ovariectomized rats, Alcohol, 2:641-646, 1985;Dhariwal, A. et al., Separation of follicle-stimulatinghormone-releasing factor from luteinizing hormone-releasing factor,Endocrinology, 76:290-294, 1965; Dhariwal, A. et al., Chromatographicbehavior of follicle stimulating hormone-releasing factor on Sephadexand carboxy methyl cellulose, Neuroendocrinology, 2:294-303,1967;Igarashi, M. et al., A hypothalamic follicle stimulatinghormone-releasing factor, Endocrinology, 74:446-452,1964; Lumpkin, M. etal., Effect of destruction of the dorsal anterior hypothalamus onfollicle-stimulating hormone secretion in the rat, Endocrinology,115:2473-2480, 1984; Samson, W. et al., Chromatographic and biologicanalysis of ME and OVLT LHRH, Peptides, 1:97-102, 1980; Mizunuma, H., etal., Evidence for an FSH-releasing factor in the posterior portion ofthe rat median eminence, Life Sci., 33:2003-2009, 1983.

[0006] Luteinizing hormone releasing hormone (LHRH, also known asgonadotropin-releasing hormone, or GnRH) has both LH-releasing activityand FSH-releasing activity. See Schally, A. et al.,Gonadotropin-releasing hormone: one polypeptide regulates secretion ofluteinizing and follicle-stimulating hormones, Science, 173:1036-1038,1971; and D. Lincoln, Gonadotropin-releasing hormone (GnRH): basicphysiology, pp. 218-229 in L. DeGroot et al., Endocrinology, 1995. Thelatter states at page 218: “There is no convincing evidence for theexistence of a separate and specific FSH-releasing hormone, althoughsome components of the GnRH precursor and some GnRH analogues appear todiffer in the degree to which they stimulate the secretion of the twogonadotropins.”

[0007] Sower, S. et al., Primary structure and biological activity of athird gonadotropin-releasing hormone from lamprey brain, Endocrinology,132:1125-1131, 1993 reported the structure of lamprey GnRH-III (referredto as l-LHRH-III in this specification), and reported that it stimulatedestradiol and progesterone release from Petromyzon marinus (lamprey)ovaries. (Lampreys, jawless fish, are representatives of what isgenerally considered to be the most primitive of the extant classes ofvertebrates.).

[0008] Lamprey l-LHRH-I has been reported to have relatively lowactivity in releasing either FSH or LH in rats. Yu, W. et al., SelectiveFSH-releasing activity of [D-Trp⁹]GAP₁₋₁₃: comparison withgonadotropin-releasing abilities of analogs of GAP and natural LHRHs,Brain Res. Bull., 25:867-873, 1990.

[0009] Schally, A. et al., Re-examination of porcine and bovinehypothalamic fractions for additional luteinizing hormone and folliclestimulating hormone-releasing activities, Endocrinology, 98:380-391,1976 reported that in vivo FSH-releasing activity could not be separatedfrom LH-releasing activity from porcine hypothalami by fractionation onSephadex, and concluded that there was only one gonadotropin-releasinghormone (GnRH).

[0010] By contrast, Lumpkin, M. et al., Purification of FSH-releasingfactor: Its dissimilarity from LHRH of mammalian, avian, and piscianorigin, Brain Res. Bull., 18:175-178, 1987 reported that FSH-releasingactivity was separated from the LH-releasing activity in ovinehypothalami on Sephadex G-25, but did not isolate the factor causing FSHrelease.

[0011] Neurons that are immunopositive for l-LHRH-I have been identifiedin human hypothalami, projecting from the arcuate region to the medianeminence. Stopa, E. et al, Polygenic expression ofgonadotropin-releasing hormone (GnRH) in human?, Peptides, 9:419-423,1988.

[0012] Lincoln, D., Luteinizing Hormone-Releasing Hormone, pp. 142-151in DeGroot et al. (ed), Endocrinology, 1989, discloses various agonistsand antagonists for mammalian LHRH.

[0013] W. Yu et al., “A hypothalamic follicle-stimulatinghormone-releasing decapeptide in the rat,” Proc. Natl. Acad. Sci. USA,94:9499-9503, 1997 discloses some of the work reported in the presentspecification, but is not believed to constitute prior art.

[0014] U.S. Pat. No. 4,973,577 discloses a 28,000 dalton proteinisolated from porcine follicular fluid that stimulates the release ofFSH, but not of LH. This protein has a relatively slow onset of action,and is relatively difficult to synthesize. The protein was said to be ahomodimer of two chains of 116 amino acid residues each, or 232 residuestotal.

[0015] U.S. Pat. No. 3,888,836 discloses a method for synthesizingmammalian LHRH. Mammalian LHRH causes increased serum levels of both LHand FSH.

[0016] U.S. Pat. No. 4,721,775 discloses certain peptides thatnon-selectively induce the secretion of both LH and FSH.

[0017] Attempts in our laboratory to purify FSH-releasing factor(FSH-RF) by fractionation of lamb hypothalami (discussed in some of thepapers cited above) were successful only at certain seasons of the year,and even then we found that activity was lost after samples were storedat −20° C. (unpublished data). Thus our prior work did not successfullyisolate or identify the putative FSH-releasing factor.

[0018] Other studies in our laboratory confirmed FSH-releasing activityby incubating stalk-median eminence (SME)-extracts in vitro withhemipituitaries from male rats. We confirmed the FSH-releasing activityof sheep and rat SME extracts in this assay, and found that theFSH-releasing activity emerged from columns of Sephadex G-25 just priorto emergence of LHRH, similar to results we had seen in an in vivo assayin ovariectomized, estrogen- and progesterone-blocked female rats. Evenwhere we were able to extract crude or partially purified fractionsshowing selective FSH-releasing activity, that activity was relativelylow compared to the activity of fractions with LH-releasing activity(unpublished data).

[0019] Our laboratory also screened known LHRH's from various speciesfor selective FSH-releasing activity; and we also evaluated the activityof 25 analogs of LHRH in in vivo assays. (LHRH's from various speciesare disclosed in Lumpkin et al., 1987.) One analog was found to haveonly FSH-releasing activity, but its potency was very low, and the slopeof its dose-response curve was flat. Of the known forms of LHRH fromother species, we found that only chicken (c) LHRH-II had slightlypreferential FSH-releasing activity in vivo (unpublished data).

DISCLOSURE OF INVENTION

[0020] We have unexpectedly discovered that l-LHRH-III is thelong-sought FSH-releasing factor. This activity has been confirmed invitro by incubation with hemi-anterior pituitaries of adult male rats.Following intravenous injection at the lowest dose tested to date (10picomoles), this peptide produced an increase in FSH in vivo (P<0.01)within ten minutes, but no significant increase in LH. Such a selectiveeffect has not previously been reported for any analog of mammalianLHRH.

MODES FOR CARRYING OUT THE INVENTION

[0021] TABLE 1 Structure of Vertebrate LHRH's Tested MammalpGlu-His-Trp-Ser- Tyr-Gly-Leu-Arg - Pro-Gly-NH₂ (SEQ. ID NO.2) (m-LHRH)Lamprey III pGlu-His-Trp-Ser- His-Asp-Trp-Lys - Pro-Gly-NH₂ (SEQ. IDNO.1) (l-LHRH-llI) Lamprey I pGlu-His-Tyr-Ser-Leu-Glu-Trp-Lys-Pro-Gly-NH₂ (SEQ. ID NO.3) (l-LHRH-I) SalmonpGlu-His-Trp-Ser-Tyr-Gly-Trp-Leu- Pro-Gly-NH₂ (SEQ. ID NO.4) (s-LHRH)Chicken II pGlu-His-Trp-Ser-His-Gly-Trp-Tyr- Pro-Gly-NH₂ (SEQ. ID NO.5)(c-LHRH-ll)

[0022] General

[0023] Adult male and female Sprague-Dawley rats (Holtzmann, Madison,Wis.; 200-250 g) were housed two per cage under controlled conditions oftemperature (23-25° C.) and lighting (on from 0500 to 1700 hr). Theanimals had free access to a pellet diet and to tap water.

[0024] The l-LHRH-III used in the experiments reported here wassynthesized by standard solid-state peptide synthesis methods, and waspurified to greater than 97% purity by preparative reverse-phase highperformance liquid chromatography. All other peptides used werepurchased from Peninsula Laboratories (Belmont, Calif.), except asotherwise noted.

[0025] The significance of differences among multiple groups wasdetermined by analysis of variance, with subsequent Newman-Keulsmultiple comparisons at each point. Student's t-test was used todetermine the significance of differences between two groups.

[0026] In Vitro Studies

[0027] After acclimatization for 5 or more days in the vivarium, malerats were killed by decapitation. Following removal of the posteriorlobe, the anterior pituitary (AP) was bisected longitudinally, and eachAP was incubated in a tube containing 0.5 ml Krebs-Ringer bicarbonate (5mM ascorbic acid; pH 7.4) buffer (KRB) in an atmosphere of 95% O₂/5% CO₂in a Dubnoff shaker (50 cycles per min) for a period of 60 min.Following this pre-incubation period, the APs were incubated for 3 hr infresh KRB buffer alone (control), or in KRB containing one of variousconcentrations of synthetic mammalian (m)-LHRH, l-LHRH-III, l-LHRH-I,chicken (c)-LHRH-II, or salmon (s)-LHRH. The medium was then aspirated,and was stored frozen at −20° C. until radio-immunoassays (RIA) for FSHand LH were conducted. FSH and LH were measured using kits supplied bythe National Institute of Arthritis Digestive Diabetes and KidneyDisease; hormone values were expressed in terms of NIH-rFSH-RP-2 andNIH-rLH-RP-3 standards. The experiments were repeated twice. The inter-and intra-assay coefficients of variation for FSH assays were 7.5% and5.2%, respectively; and were 6.5% and 4.8% for LH assays.

[0028] In Vivo Studies

[0029] Female rats were ovariectomized under anesthesia with isoflurane4 weeks prior to the in vivo experiments. Three days before bloodsampling, each ovariectomized rat was injected subcutaneously with 50 μgestradiol benzoate (Sigma Chemical Co., St. Louis, Mo.) dissolved in 0.1 ml sesame oil, and 25 mg progesterone (Eli Lilly, Indianapolis, Ind.)dissolved in 0.5 ml sesame oil. One day prior to testing, each animalwas implanted with a jugular-atrial catheter. On the morning of testing,polyethylene tubing (PE-50) was connected to the distal end of thejugular-atrial catheter on the rat's dorsum to facilitate blood samplingand intravenous injection. Animals were acclimatized one hour beforeinitial blood samples were taken. Heparinized blood samples (5 ml) werecollected just before, and at 10, 30, and 60 minutes after injection of0.5 ml isotonic saline or l-LHRH-III (10 or 100 pmole) in 0.5 mlisotonic saline. After removal of each blood sample, an equal volume ofisotonic saline was administered to maintain blood volume.

[0030] Effects of l-LHRH-I, l-LHRH-III, and Mammalian (m)-LHRH on FSHRelease in Vitro

[0031] Lamprey l-LHRH-III caused FSH release in a dose-related fashion,with a minimal effective concentration (MEC) of 10⁻⁹ M (the lowestconcentration tested) or lower, and a maximal effect at about 10⁻⁶ M.Thereafter, release of FSH levelled off through the highestconcentration tested (10⁻⁴ M).

[0032] Lamprey l-LHRH-I caused a small but statistically significantrelease of FSH at a concentration of 10⁻⁵ M; the amount of FSH releasedwas significantly less than that caused by l-LHRH-III at the twoconcentrations tested (10⁻⁶ and 10⁻⁵ M). By contrast, m-LHRH producedequivalent levels of FSH release at the two concentrations tested(4×10⁻⁹ and 2×10⁻⁸ M) as compared to the levels induced by l-LHRH-III.See Table 2. TABLE 2 Group FSH (ng/ml) KRB (control)   97.7 ± 20.4m-LHRH, 4 × 10⁻⁹ M **218.5 ± 35.7 m-LHRH, 2 × 10⁻⁸ M **257.5 ± 42.4l-LHRH-III, 10⁻⁹ M  *228.3 ± 52.5 l-LHRH-III, 10⁻⁸ M **255.7 ± 42.4l-LHRH-III, 10⁻⁷ M ***213.0 ± 17.9  l-LHRH-III, 10⁻⁶ M **278.2 ± 40.9l-LHRH-III, 10⁻⁵ M **283.0 ± 60.8 l-LHRH-III, 10⁻⁴ M ****368.6 ± 40.9 l-LHRH-I, 10⁻⁶ M  *164.0 ± 29.3 l-LHRH-I, 10⁻⁵ M **178.2 ± 17.0

[0033] Effect of l-LHRH-I, l-LHRH-III, and m-LHRH on LH Release in Vitro

[0034] In contrast to its effects on FSH release, l-LHRH-III had a muchweaker effect on LH release. In fact, l-LHRH-III only caused the releaseof significant and comparable concentrations of LH at the three highestconcentrations tested (10⁻⁶−10⁻⁴ M). We found that l-LHRH-I was inactiveat the two concentrations tested (10⁻⁶ and 10⁻⁵ M). Mammalian LHRH gavea dose-related stimulatory effect on LH release, and was active at thelowest concentration tested (4×10⁻⁹ M). See Table 3. TABLE 3 Group LH(ng/ml) KRB (control) 139.3 ± 16.9 m-LHRH, 4 × 10⁻⁹ M 183.1 ± 27.0m-LHRH, 2 × 10⁻⁸ M **262.0 ± 36.1  l-LHRH-III, 10⁻⁹ M 171.8 ± 27.3l-LHRH-III, 10⁻⁸ M 165.7 ± 26.6 l-LHRH-III, 10⁻⁷ M 179.9 ± 28.4l-LHRH-III, 10⁻⁶ M *233.6 ± 33.8  l-LHRH-III, 10⁻⁵ M *202.9 ± 31.2 l-LHRH-III, 10⁻⁴ M **236.6 ± 19.3  l-LHRH-I, 10⁻⁶ M 134.1 ± 23.2l-LHRH-I, 10⁻⁵ M 120.4 ± 8.1 

[0035] Effects of Salmon and Chicken LHRH-II on Gonadotropin Release inVitro

[0036] Salmon (s)-LHRH stimulated the release of both FSH and LH at thetwo concentrations tested (10⁻⁷ and 10⁻⁶ M). See Tables 4 and 5. Chicken(c) LHRH-II stimulated LH release at doses from 10⁻⁸ to 10⁻⁶ M, but thedose effect was not statistically significant. The c-LHRH-II hadequivalent LH-releasing activity to that of m-LHRH, but l-LHRH-IIIshowed no LH-releasing activity in this experiment. The c-LHRH-II onlysignificantly increased FSH release at the highest concentration tested(10⁻⁶ M). In this experiment, the MEC for l-LHRH-III for a statisticallysignificant release of FSH was two orders of magnitude lower than thatfor c-LHRH-II. TABLE 4 Group FSH (ng/ml) KRB (control) 157.5 ± 13.2m-LHRH, 2 × 10⁻⁸ M **320.5 ± 42.6  l-LHRH-III, 10⁻⁹ M 196.3 ± 21.2l-LHRH-III, 10⁻⁸ M *249.3 ± 31.3  l-LHRH-III, 10⁻⁷ M *203.2 ± 16.4 l-LHRH-III, 10⁻⁶ M 215.0 ± 38.0 c-LHRH-II, 10⁻⁸ M 123.7 ± 18.0c-LHRH-II, 10⁻⁷ M 209.3 ± 44.0 c-LHRH-II, 10⁻⁶ M ***263.7 ± 17.8  s-LHRH, 10⁻⁷ M *233.0 ± 37.4  s-LHRH, 10⁻⁶ M 203.2 ± 39.2

[0037] TABLE 5 Group LH (ng/ml) KRB (control) 149.3 ± 17.0 m-LHRH, 2 ×10⁻⁸ M *214.7 ± 30.3  l-LHRH-III, 10⁻⁹ M 158.7 ± 10.2 l-LHRH-III, 10⁻⁸ M163.2 ± 6.5  l-LHRH-III, 10⁻⁷ M 182.7 ± 13.7 l-LHRH-III, 10⁻⁶ M 176.0 ±9.3  c-LHRH-II, 10⁻⁸ M *199.3 ± 13.6  c-LHRH-II, 10⁻⁷ M *216.3 ± 17.7 c-LHRH-II, 10⁻⁶ M *239.0 ± 31.7  s-LHRH, 10⁻⁷ M *230.8 ± 38.8  s-LHRH,10⁻⁶ M 186.2 ± 13.6

[0038] Effects of l-LHRH-III on FSH and LH Release in Vivo

[0039] Saline-injected control animals experienced a significant declinein plasma FSH levels 10 minutes after injection, followed by a return tolevels that did not differ significantly from pre-injection FSH levelsby 30- and 60-minutes post-injection (data not shown).

[0040] Compared to the control animals, animals injected with the lowestdose of l-LHRH-III (10 pmole) showed a highly significant increase inplasma FSH 10 minutes after injection, an effect that vanished by 30minutes post-injection. See Table 6. Increasing the dose of l-LHRH-IIIto 100 pmole produced a slightly greater effect at 10 minutes that wasmaintained 30 minutes after injection. Thus the 100 pmole dose caused amore prolonged effect than the 10 pmole dose. TABLE 6 Change in FSH frombaseline, Group 10 minutes post-injection (ng/ml) saline −3.85 ± 0.82l-LHRH-III, 10 pmole **−0.75 ± 0.37  l-LHRH-III, 100 pmole **−0.43 ±0.61 

[0041] Injection of saline diluent produced a slight decrease in LHplasma concentration 10 minutes post-injection, an effect that continuedfor the duration of the experiment, but that was not statisticallysignificant. Neither the 10 pmole nor the 100 pmole dose of l-LHRH-IIIproduced a statistically significant difference in LH levels versussaline control at any of the times measured. See Table 7. TABLE 7 Changein LH from baseline, Group 10 minutes post-injection (ng/ml) saline−0.070 ± 0.122  l-LHRH-III, 10 pmole −0.022 ± 0.078  l-LHRH-III, 100pmole 0.097 ± 0.077

[0042] Thus l-LHRH-III caused the release of FSH in vivo, but not LH, ateach of the two doses tested, 10 pmole and 100 pmole.

[0043] As these results have demonstrated, l-LHRH-III is the firsthighly specific and potent FSH-releasing peptide discovered. Thel-LHRH-III behaves completely differently from the other polypeptidestested. We found that l-LHRH-I had minimal potency to release either FSHor LH. Salmon LHRH and chicken LHRH-II had low potency, and lackedspecificity for FSH release. The in vivo assays using the other knownvertebrate LHRH's showed that only one of them, c-LHRH-II, possessedeven slight selectivity for FSH release.

[0044] We conclude that l-LHRH-III is a highly conserved peptide invertebrates, and in particular that it or a closely related peptide isthe mammalian peptide hormone responsible for the potent and specificrelease of FSH. If l-LHRH-III is not identical to the mammalian FSH-RF,the degree of homology between the two is quite high.

[0045] Mammalian m-LHRH and l-LHRH-III were approximately equipotenttoward releasing FSH. The decreased potency of l-LHRH-III towardreleasing LH is probably accounted for by the fact that l-LHRH-III onlyhas 60% homology with m-LHRH (see Table 1). The differences in sequencesare accounted for by the differing amino acids in positions 5-8, whichpresumably cause a drastic decrease in LH-releasing activity and anincrease in FSH-releasing capabilities. It is probable that thetetrapeptide l-LHRH-III 5-8 binds to the active site of a putativespecific FSH-RF receptor. Presumably, the FSH-RF receptor confers thisspecificity for FSH release, whereas the LHRH receptors stimulate therelease of both hormones, albeit with a greater sensitivity for LH thanFSH release. FSH-RF receptors may reside on gonadotropes that containonly FSH. LHRH receptors may cause release of both hormones fromgonadotropes that contain both FSH and LH. LHRH receptors may also belocated on gonadotropes that only contain LH.

[0046] Pulsatile gonadotropin release in the rat is characterized bysimultaneous pulses of FSH and LH, by pulses of LH alone, and by pulsesof FSH alone. We hypothesize that the first two types of pulses may beaccounted for by LHRH, and the third by FSH-RF.

[0047] The discovery of FSH-RF has important implications for veterinaryand human medicine. For example, treatment of farm animals with FSH-RFshould lead to maturation of increased numbers of ovarian follicles andsubsequent ovulations, leading to increased litter sizes. FSH-RF may beused as a drug to increase fertility in humans.

[0048] Related peptides are expected to be agonists or “superagonists”of l-LHRH-III. These agonists will be prepared and tested in similarassays. Particular examples include peptides in which (a) the Asp⁶ aminoacid residue has been replaced with another amino acid residue(naturally occurring or xenobiotic); or (b) in which the Pro⁹ residuehas been replaced with ProNHEt (prolyl ethyl amide) and the Gly¹⁰-NH₂has been deleted; or (c) both. Examples of such agonists include thefollowing:

[0049] pGlu-His-Trp-Ser-His-Asp-Trp-Lys-(ProNHEt) (SEQ. ID NO. 6)

[0050] pGlu-His-Trp-Ser-His-Ala-Trp-Lys-Pro-Gly-NH₂ (SEQ. ID NO. 7)

[0051] pGlu-His-Trp-Ser-His-Ala-Trp-Lys-(ProNHEt) (SEQ. ID NO. 8)

[0052] pGlu-His-Trp-Ser-His-(D-Ala)-Trp-Lys-Pro-Gly-NH₂ (SEQ. ID NO. 9)

[0053] pGlu-His-Trp-Ser-His-(D-Ala)-Trp-Lys-(ProNHEt) (SEQ. ID NO. 10)

[0054] pGlu-His-Trp-Ser-His-Leu-Trp-Lys-Pro-Gly-NH₂ (SEQ. ID NO. 11)

[0055] pGlu-His-Trp-Ser-His-Leu-Trp-Lys-(ProNHEt) (SEQ. ID NO. 12)

[0056] pGlu-His-Trp-Ser-His-(D-Leu)-Trp-Lys-Pro-Gly-NH₂ (SEQ. ID NO. 13)

[0057] pGlu-His-Trp-Ser-His-(D-Leu)-Trp-Lys-(ProNHEt) (SEQ. ID NO. 14)

[0058] pGlu-His-Trp-Ser-His-(SerBu^(t))-Trp-Lys-Pro-Gly-NH₂ (SEQ. ID NO.15)

[0059] pGlu-His-Trp-Ser-His-(SerBu^(t))-Trp-Lys-(ProNHEt) (SEQ. ID NO.16)

[0060] pGlu-His-Trp-Ser-His-(D-SerBu^(t))-Trp-Lys-Pro-Gly-NH₂ (SEQ. IDNO. 17)

[0061] pGlu-His-Trp-Ser-His-(D-SerBu^(t))-Trp-Lys-(ProNHEt) (SEQ. ID NO.18)

[0062] pGlu-His-Trp-Ser-His-Trp-Trp-Lys-Pro-Gly-NH₂ (SEQ. ID NO. 19)

[0063] pGlu-His-Trp-Ser-His-Trp-Trp-Lys-(ProNHEt) (SEQ. ID NO. 20)

[0064] pGlu-His-Trp-Ser-His-(D-Trp)-Trp-Lys-Pro-Gly-NH₂ (SEQ. ID NO. 21)

[0065] pGlu-His-Trp-Ser-His-(D-Trp)-Trp-Lys-(ProNHEt) (SEQ. ID NO. 22)

[0066] pGlu-His-Trp-Ser-His-(His-Bzl)-Trp-Lys-Pro-Gly-NH₂ (SEQ. ID NO.23)

[0067] pGlu-His-Trp-Ser-His-(His-Bzl)-Trp-Lys-(ProNHEt) (SEQ. ID NO. 24)

[0068] pGlu-His-Trp-Ser-His-(D-His-Bzl)-Trp-Lys-Pro-Gly-NH₂ (SEQ. ID NO.25)

[0069] pGlu-His-Trp-Ser-His-(D-His-Bzl)-Trp-Lys-(ProNHEt) (SEQ. ID NO.26)

[0070] pGlu-His-Trp-Ser-His-Nal(2)-Trp-Lys-Pro-Gly-NH₂ (SEQ. ID NO. 27)

[0071] pGlu-His-Trp-Ser-His-Nal(2)-Trp-Lys-(ProNHEt) (SEQ. ID NO. 28)

[0072] pGlu-His-Trp-Ser-His-(D-Nal(2))-Trp-Lys-Pro-Gly-NH₂ (SEQ. ID NO.29)

[0073] pGlu-His-Trp-Ser-His-(D-Nal(2))-Trp-Lys-(ProNHEt) (SEQ. ID NO.30)

[0074] pGlu-His-Trp-Ser-His-Nal(2)-Trp-Lys-Pro-(aza-Gly)-NH₂ (SEQ. IDNO. 31)

[0075] pGlu-His-Trp-Ser-His-(D-Nal(2))-Trp-Lys-Pro-(aza-Gly)-NH₂ (SEQ.ID NO. 32)

[0076] Note: “(aza-Gly)-NH₂” in SEQ. ID NOs. 31 and 32 denotes—NH—NH—CONH₂.

[0077] Conversely, inhibitory analogs of the peptide, or antibodiesagainst the peptide, maybe used as potent antifertility drugs.Monoclonal or polyclonal antibodies against the peptide may be raisedusing standard techniques, initially conjugating the peptide to acarrier such as bovine serum albumin or keyhole limpet hemocyanin.Particular examples of antagonists include peptides in which one or moreof residues 1, 2, 3, 6, and 10 have been replaced with another aminoacid residue (naturally occurring or xenobiotic). Examples of suchantagonists include the following:

[0078] pGlu-(D-Phe)-Trp-Ser-His-(D-Ala)-Trp-Lys-Pro-Gly-NH₂ (SEQ. ID NO.33)

[0079] pGlu-(D-Phe)-(D-Trp)-Ser-His-(D-Trp)-Trp-Lys-Pro-Gly-NH₂ (SEQ. IDNO. 34)

[0080] (D-pyro-Glu)-(D-Phe)-(D-Trp)-Ser-His-(D-Trp)-Trp-Lys-Pro-Gly-NH₂(SEQ. ID NO. 35)(N-Ac-D-Phe)-(D-p-Cl-Phe)-(D-Trp)-Ser-His-(D-Trp)-Trp-Lys-Pro-Gly-NH₂(SEQ. ID NO.36)(N-Ac-D-p-Cl-Phe)-(Ac-D-p-Cl-Phe)-(D-Trp)-Ser-His-(D-Phe)-Trp-Lys-Pro-(D-Ala)-NH₂(SEQ. ID NO.37)(N-Ac-D-p-Cl-Phe)-(Ac-D-p-Cl-Phe)-(D-Trp)-Ser-His-(D-Arg)-Trp-Lys-Pro-(D-Ala)-NH₂(SEQ. ID NO.38)(N-Ac-D-Nal(2))-(p-F-D-Phe)-(D-Trp)-Ser-His-(D-Arg)-Trp-Lys-Pro-Gly-NH₂(SEQ. ID NO.39)(N-Ac-D-Nal(2))-(D-p-Cl-Phe)-(D-Trp)-Ser-His-(D-L-Arg-Et²)-Trp-Lys-Pro-(D-Ala)-NH₂(SEQ. ID NO.40)(N-Ac-D-Nal(2))-(D-p-Cl-Phe)-(D-3-Pal)-Ser-His-(D-Arg)-(D-Trp)-Lys-Pro-(D-Ala)-NH₂(SEQ. ID NO.41)

[0081] The effect of the peptide, its agonists, and its antagonists willbe characterized in rats, and then in large mammals, such as sheep andpigs. After successful testing in large mammals, in vivo tests inprimates will be conducted, in monkeys and in humans, in accordance withapplicable laws and regulations.

[0082] The peptide, an agonist, or an antagonist, combined with apharmaceutically acceptable carrier, may be administered to mammals,including humans, intravenously, subcutaneously, percutaneously,intramuscularly, or intranasally to increase fertility. It may also beadministered to other vertebrates to increase fertility, for examplesheep, cattle, pigs, chickens, turkeys, channel catfish, tilapia, andkoi.

[0083] The active compound may be administered as a pharmaceuticallyacceptable salt, such as an acid addition salt; metal complex, e.g. withzinc, iron; or the like (which are considered salts for purposesherein). Illustrative of such acid addition salts are hydrochloride,hydrobromide, sulfate, phosphate, maleate, acetate, citrate, benzoate,succinate, malate, ascorbate, tartrate, and the like. Intravenous orother injections may be administered in isotonic saline, phosphatebuffers, and the like.

[0084] The dosage will vary depending on the specific purpose for whichthe peptide is administered; appropriate dosages may readily bedetermined by those of skill in the art, an “effective amount” beingthat which elevates or depresses serum FSH levels by a statisticallysignificant amount, or that which enhances or inhibits fertility to astatistically significant degree.

[0085] For example, a patient experiencing infertility of unknown causemay be tested for l-LHRH-III or FSH deficit through means otherwiseknown in the art, such as radioimmunoassay. Abnormally low FSH levelsmay indicate a deficiency in l-LHRH-III. Such patients may be tested fora positive response to exogenous l-LHRH-III. If administration ofexogenous l-LHRH-III produces an increase in FSH, that finding indicatesthat administration of exogenous l-LHRH-III is a potential treatment forinfertility.

[0086] As may prove most economical, the l-LHRH-III may be synthesizedthrough any of various means known in the art, for example, synthesis ona solid-state peptide synthesizer, or expression of a cloned gene in E.coli.

[0087] The complete disclosures of all references cited in thisspecification are hereby incorporated by reference. In the event of anotherwise irreconcilable conflict, however, the present specificationshall control.

0 SEQUENCE LISTING (1) GENERAL INFORMATION: (iii) NUMBER OF SEQUENCES:41 (2) INFORMATION FOR SEQ ID NO: 1: (i) SEQUENCE CHARACTERISTICS: (A)LENGTH: 10 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii)MOLECULE TYPE: peptide (ix) FEATURE: (D) OTHER INFORMATION:/note= “Xaaat 1 is pyro-Glu; Xaa at 10 is Gly-NH2” (xi) SEQUENCE DESCRIPTION: SEQID NO: 1: Xaa His Trp Ser His Asp Trp Lys Pro Xaa 1 5 10 (2) INFORMATIONFOR SEQ ID NO: 2: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 10 aminoacids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE:peptide (ix) FEATURE: (D) OTHER INFORMATION:/note= “Xaa at 1 ispyro-Glu; Xaa at 10 is Gly-NH2” (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 2:Xaa His Trp Ser Tyr Gly Leu Arg Pro Xaa 1 5 10 (2) INFORMATION FOR SEQID NO: 3: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 10 amino acids (B)TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix)FEATURE: (D) OTHER INFORMATION:/note= “Xaa at 1 is pyro-Glu; Xaa at 10is Gly-NH2” (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 3: Xaa His Tyr Ser LeuGlu Trp Lys Pro Xaa 1 5 10 (2) INFORMATION FOR SEQ ID NO: 4: (i)SEQUENCE CHARACTERISTICS: (A) LENGTH: 10 amino acids (B) TYPE: aminoacid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (D)OTHER INFORMATION:/note= “Xaa at 1 is pyro-Glu; Xaa at 10 is Gly-NH2”(xi) SEQUENCE DESCRIPTION: SEQ ID NO: 4: Xaa His Trp Ser Tyr Gly Trp LeuPro Xaa 1 5 10 (2) INFORMATION FOR SEQ ID NO: 5: (i) SEQUENCECHARACTERISTICS: (A) LENGTH: 10 amino acids (B) TYPE: amino acid (D)TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (D) OTHERINFORMATION:/note= “Xaa at 1 is pyro-Glu; Xaa at 10 is Gly-NH2” (xi)SEQUENCE DESCRIPTION: SEQ ID NO: 5: Xaa His Trp Ser His Gly Trp Tyr ProXaa 1 5 10 (2) INFORMATION FOR SEQ ID NO: 6: (i) SEQUENCECHARACTERISTICS: (A) LENGTH: 9 amino acids (B) TYPE: amino acid (D)TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (D) OTHERINFORMATION:/note= “Xaa at 1 is pyro-Glu; Xaa at 9 is (ProNHEt)” (xi)SEQUENCE DESCRIPTION: SEQ ID NO: 6: Xaa His Trp Ser His Asp Trp Lys Xaa1 5 (2) INFORMATION FOR SEQ ID NO: 7: (i) SEQUENCE CHARACTERISTICS: (A)LENGTH: 10 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii)MOLECULE TYPE: peptide (ix) FEATURE: (D) OTHER INFORMATION:/note= “Xaaat 1 is pyro-Glu; Xaa at 10 is Gly-NH2” (xi) SEQUENCE DESCRIPTION: SEQID NO: 7: Xaa His Trp Ser His Ala Trp Lys Pro Xaa 1 5 10 (2) INFORMATIONFOR SEQ ID NO: 8: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 9 aminoacids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE:peptide (ix) FEATURE: (D) OTHER INFORMATION: /note= “Xaa at 1 ispyro-Glu; Xaa at 9 is (ProNHEt)” (xi) SEQUENCE DESCRIPTION: SEQ ID NO:8: Xaa His Trp Ser His Ala Trp Lys Xaa 1 5 (2) INFORMATION FOR SEQ IDNO: 9: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 10 amino acids (B)TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix)FEATURE: (D) OTHER INFORMATION: /note= “Xaa at 1 is pyro-Glu; Xaa at 6is (D-Ala); Xaa at 10 is Gly-NH2” (xi) SEQUENCE DESCRIPTION: SEQ ID NO:9: Xaa His Trp Ser His Xaa Trp Lys Pro Xaa 1 5 10 (2) INFORMATION FORSEQ ID NO: 10: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 9 amino acids(B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide(ix) FEATURE: (D) OTHER INFORMATION: /note= “Xaa at 1 is pyro-Glu; Xaaat 6 is (D-Ala); Xaa at 9 is (ProNHEt)” (xi) SEQUENCE DESCRIPTION: SEQID NO: 10: Xaa His Trp Ser His Xaa Trp Lys Xaa 1 5 (2) INFORMATION FORSEQ ID NO: 11: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 10 amino acids(B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide(ix) FEATURE: (D) OTHER INFORMATION:/note= “Xaa at 1 is pyro-Glu; Xaa at10 is Gly-NH2” (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 11: Xaa His Trp SerHis Leu Trp Lys Pro Xaa 1 5 10 (2) INFORMATION FOR SEQ ID NO: 12: (i)SEQUENCE CHARACTERISTICS: (A) LENGTH: 9 amino acids (B) TYPE: amino acid(D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (D) OTHERINFORMATION: /note= “Xaa at 1 is pyro-Glu; Xaa at 9 is (ProNHEt)” (xi)SEQUENCE DESCRIPTION: SEQ ID NO: 12: Xaa His Trp Ser His Leu Trp Lys Xaa1 5 (2) INFORMATION FOR SEQ ID NO: 13: (i) SEQUENCE CHARACTERISTICS: (A)LENGTH: 10 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii)MOLECULE TYPE: peptide (ix) FEATURE: (D) OTHER INFORMATION: /note= “Xaaat 1 is pyro-Glu; Xaa at 6 is (D-Leu); Xaa at 10 is Gly-NH2” (xi)SEQUENCE DESCRIPTION: SEQ ID NO: 13: Xaa His Trp Ser His Xaa Trp Lys ProXaa 1 5 10 (2) INFORMATION FOR SEQ ID NO: 14: (i) SEQUENCECHARACTERISTICS: (A) LENGTH: 9 amino acids (B) TYPE: amino acid (D)TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (D) OTHERINFORMATION: /note= “Xaa at 1 is pyro-Glu; Xaa at 6 is (D-Leu); Xaa at 9is (ProNHEt)” (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 14: Xaa His Trp SerHis Xaa Trp Lys Xaa 1 5 (2) INFORMATION FOR SEQ ID NO: 15: (i) SEQUENCECHARACTERISTICS: (A) LENGTH: 10 amino acids (B) TYPE: amino acid (D)TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (D) OTHERINFORMATION: /note= “Xaa at 1 is pyro-Glu; Xaa at 6 is (SerBut); Xaa at10 is Gly-NH2” (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 15: Xaa His Trp SerHis Xaa Trp Lys Pro Xaa 1 5 10 (2) INFORMATION FOR SEQ ID NO: 16: (i)SEQUENCE CHARACTERISTICS: (A) LENGTH: 9 amino acids (B) TYPE: amino acid(D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (D) OTHERINFORMATION: /note= “Xaa at 1 is pyro-Glu; Xaa at 6 is (SerBut); Xaa at9 is (ProNHEt)” (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 16: Xaa His TrpSer His Xaa Trp Lys Xaa 1 5 (2) INFORMATION FOR SEQ ID NO: 17: (i)SEQUENCE CHARACTERISTICS: (A) LENGTH: 10 amino acids (B) TYPE: aminoacid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (D)OTHER INFORMATION: /note= “Xaa at 1 is pyro-Glu; Xaa at 6 is (D-SerBut);Xaa at 10 is Gly-NH2” (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 17: Xaa HisTrp Ser His Xaa Trp Lys Pro Xaa 1 5 10 (2) INFORMATION FOR SEQ ID NO:18: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 9 amino acids (B) TYPE:amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix)FEATURE: (D) OTHER INFORMATION: /note= “Xaa at 1 is pyro-Glu; Xaa at 6is (D-SerBut); Xaa at 9 is (ProNHEt)” (xi) SEQUENCE DESCRIPTION: SEQ IDNO: 18: Xaa His Trp Ser His Xaa Trp Lys Xaa 1 5 (2) INFORMATION FOR SEQID NO: 19: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 10 amino acids (B)TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix)FEATURE: (D) OTHER INFORMATION:/note= “Xaa at 1 is pyro-Glu; Xaa at 10is Gly-NH2” (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 19: Xaa His Trp SerHis Trp Trp Lys Pro Xaa 1 5 10 (2) INFORMATION FOR SEQ ID NO: 20: (i)SEQUENCE CHARACTERISTICS: (A) LENGTH: 9 amino acids (B) TYPE: amino acid(D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (D) OTHERINFORMATION: /note= “Xaa at 1 is pyro-Glu; Xaa at 9 is (ProNHEt)” (xi)SEQUENCE DESCRIPTION: SEQ ID NO: 20: Xaa His Trp Ser His Trp Trp Lys Xaa1 5 (2) INFORMATION FOR SEQ ID NO: 21: (i) SEQUENCE CHARACTERISTICS: (A)LENGTH: 10 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii)MOLECULE TYPE: peptide (ix) FEATURE: (D) OTHER INFORMATION: /note= “Xaaat 1 is pyro-Glu; Xaa at 6 is (D-Trp); Xaa at 10 is Gly-NH2” (xi)SEQUENCE DESCRIPTION: SEQ ID NO: 21: Xaa His Trp Ser His Xaa Trp Lys ProXaa 1 5 10 (2) INFORMATION FOR SEQ ID NO: 22: (i) SEQUENCECHARACTERISTICS: (A) LENGTH: 9 amino acids (B) TYPE: amino acid (D)TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (D) OTHERINFORMATION: /note= “Xaa at 1 is pyro-Glu; Xaa at 6 is (D-Trp); Xaa at 9is (ProNHEt)” (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 22: Xaa His Trp SerHis Xaa Trp Lys Xaa 1 5 (2) INFORMATION FOR SEQ ID NO: 23: (i) SEQUENCECHARACTERISTICS: (A) LENGTH: 10 amino acids (B) TYPE: amino acid (D)TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (D) OTHERINFORMATION: /note= “Xaa at 1 is pyro-Glu; Xaa at 6 is (His-Bzl); Xaa at10 is Gly-NH2” (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 23: Xaa His Trp SerHis Xaa Trp Lys Pro Xaa 1 5 10 (2) INFORMATION FOR SEQ ID NO: 24: (i)SEQUENCE CHARACTERISTICS: (A) LENGTH: 9 amino acids (B) TYPE: amino acid(D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (D) OTHERINFORMATION: /note= “Xaa at 1 is pyro-Glu; Xaa at 6 is (His-Bzl); Xaa at9 is (ProNHEt)” (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 24: Xaa His TrpSer His Xaa Trp Lys Xaa 1 5 (2) INFORMATION FOR SEQ ID NO: 25: (i)SEQUENCE CHARACTERISTICS: (A) LENGTH: 10 amino acids (B) TYPE: aminoacid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (D)OTHER INFORMATION: /note= “Xaa at 1 is pyro-Glu; Xaa at 6 is(D-His-Bzl); Xaa at 10 is Gly-NH2” (xi) SEQUENCE DESCRIPTION: SEQ ID NO:25: Xaa His Trp Ser His Xaa Trp Lys Pro Xaa 1 5 10 (2) INFORMATION FORSEQ ID NO: 26: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 9 amino acids(B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide(ix) FEATURE: (D) OTHER INFORMATION: /note= “Xaa at 1 is pyro-Glu; Xaaat 6 is (D-His-Bzl); Xaa at 9 is (ProNHEt)” (xi) SEQUENCE DESCRIPTION:SEQ ID NO: 26: Xaa His Trp Ser His Xaa Trp Lys Xaa 1 5 (2) INFORMATIONFOR SEQ ID NO: 27: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 10 aminoacids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE:peptide (ix) FEATURE: (D) OTHER INFORMATION: /note= “Xaa at 1 ispyro-Glu; Xaa at 6 is Nal(2); Xaa at 10 is Gly-NH2” (xi) SEQUENCEDESCRIPTION: SEQ ID NO: 27: Xaa His Trp Ser His Xaa Trp Lys Pro Xaa 1 510 (2) INFORMATION FOR SEQ ID NO: 28: (i) SEQUENCE CHARACTERISTICS: (A)LENGTH: 9 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii)MOLECULE TYPE: peptide (ix) FEATURE: (D) OTHER INFORMATION: /note= “Xaaat 1 is pyro-Glu; Xaa at 6 is Nal(2); Xaa at 9 is (ProNHEt)” (xi)SEQUENCE DESCRIPTION: SEQ ID NO: 28: Xaa His Trp Ser His Xaa Trp Lys Xaa1 5 (2) INFORMATION FOR SEQ ID NO: 29: (i) SEQUENCE CHARACTERISTICS: (A)LENGTH: 10 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii)MOLECULE TYPE: peptide (ix) FEATURE: (D) OTHER INFORMATION: /note= “Xaaat 1 is pyro-Glu; Xaa at 6 is (D-Nal(2)); Xaa at 10 is Gly-NH2” (xi)SEQUENCE DESCRIPTION: SEQ ID NO: 29: Xaa His Trp Ser His Xaa Trp Lys ProXaa 1 5 10 (2) INFORMATION FOR SEQ ID NO: 30: (i) SEQUENCECHARACTERISTICS: (A) LENGTH: 9 amino acids (B) TYPE: amino acid (D)TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (D) OTHERINFORMATION: /note= “Xaa at 1 is pyro-Glu; Xaa at 6 is (D-Nal(2)); Xaaat 9 is (ProNHEt)” (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 30: Xaa His TrpSer His Xaa Trp Lys Xaa 1 5 (2) INFORMATION FOR SEQ ID NO: 31: (i)SEQUENCE CHARACTERISTICS: (A) LENGTH: 10 amino acids (B) TYPE: aminoacid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (D)OTHER INFORMATION: /note= “Xaa at 1 is pyro-Glu; Xaa at 6 is Nal(2); Xaaat 10 is (aza-Gly)” (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 31: Xaa HisTrp Ser His Xaa Trp Lys Pro Xaa 1 5 10 (2) INFORMATION FOR SEQ ID NO:32: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 10 amino acids (B) TYPE:amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix)FEATURE: (D) OTHER INFORMATION: /note= “Xaa at 1 is pyro-Glu; Xaa at 6is (D-Nal(2)); Xaa at 10 is (aza-Gly)” (xi) SEQUENCE DESCRIPTION: SEQ IDNO: 32: Xaa His Trp Ser His Xaa Trp Lys Pro Xaa 1 5 10 (2) INFORMATIONFOR SEQ ID NO: 33: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 10 aminoacids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE:peptide (ix) FEATURE: (D) OTHER INFORMATION: /note= “Xaa at 1 ispyro-Glu; Xaa at 2 is (D-Phe); Xaa at 6 is (D-Ala); Xaa at 10 isGly-NH2” (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 33: Xaa Xaa Trp Ser HisXaa Trp Lys Pro Xaa 1 5 10 (2) INFORMATION FOR SEQ ID NO: 34: (i)SEQUENCE CHARACTERISTICS: (A) LENGTH: 10 amino acids (B) TYPE: aminoacid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (D)OTHER INFORMATION: /note= “Xaa at 1 is pyro-Glu; Xaa at 2 is (D-Phe);Xaa at 3 is (D-Trp); Xaa at 6 is (D- Trp); Xaa at 10 is Gly-NH2” (xi)SEQUENCE DESCRIPTION: SEQ ID NO: 34: Xaa Xaa Xaa Ser His Xaa Trp Lys ProXaa 1 5 10 (2) INFORMATION FOR SEQ ID NO: 35: (i) SEQUENCECHARACTERISTICS: (A) LENGTH: 10 amino acids (B) TYPE: amino acid (D)TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (D) OTHERINFORMATION: /note= “Xaa at 1 is (D-pyro-Glu); Xaa at 2 is (D-Phe); Xaaat 3 is (D-Trp); Xaa at 6 is (D-Trp); Xaa at 10 is Gly-NH2” (xi)SEQUENCE DESCRIPTION: SEQ ID NO: 35: Xaa Xaa Xaa Ser His Xaa Trp Lys ProXaa 1 5 10 (2) INFORMATION FOR SEQ ID NO: 36: (i) SEQUENCECHARACTERISTICS: (A) LENGTH: 10 amino acids (B) TYPE: amino acid (D)TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (D) OTHERINFORMATION: /note= “Xaa at 1 is (N-Ac-D-Phe); Xaa at 2 is (D-p-Cl-Phe);Xaa at 3 is (D-Trp); Xaa at 6 is (D-Trp); Xaa at 10 is Gly-NH2” (xi)SEQUENCE DESCRIPTION: SEQ ID NO: 36: Xaa Xaa Xaa Ser His Xaa Trp Lys ProXaa 1 5 10 (2) INFORMATION FOR SEQ ID NO: 37: (i) SEQUENCECHARACTERISTICS: (A) LENGTH: 10 amino acids (B) TYPE: amino acid (D)TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (D) OTHERINFORMATION: /note= “Xaa at 1 is (N-Ac-D-p-Cl-Phe); Xaa at 2 is(Ac-D-p-Cl-Phe); Xaa at 3 is (D-Trp); Xaa at 6 is (D-Phe); Xaa at 10 is(D-Ala-NH2)” (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 37: Xaa Xaa Xaa SerHis Xaa Trp Lys Pro Xaa 1 5 10 (2) INFORMATION FOR SEQ ID NO: 38: (i)SEQUENCE CHARACTERISTICS: (A) LENGTH: 10 amino acids (B) TYPE: aminoacid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (D)OTHER INFORMATION: /note= “Xaa at 1 is (N-Ac-D-p-Cl-Phe); Xaa at 2 is(Ac-D-p-Cl-Phe); Xaa at 3 is (D-Trp); Xaa at 6 is (D-Arg); Xaa at 10 is(D-Ala-NH2)” (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 38: Xaa Xaa Xaa SerHis Xaa Trp Lys Pro Xaa 1 5 10 (2) INFORMATION FOR SEQ ID NO: 39: (i)SEQUENCE CHARACTERISTICS: (A) LENGTH: 10 amino acids (B) TYPE: aminoacid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (D)OTHER INFORMATION: /note= “Xaa at 1 is (N-Ac-D-Nal(2)); Xaa at 2 is(p-F-D-Phe); Xaa at 3 is (D-Trp); Xaa at 6 is (D-Arg); Xaa at 10 isGly-NH2” (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 39: Xaa Xaa Xaa Ser HisXaa Trp Lys Pro Xaa 1 5 10 (2) INFORMATION FOR SEQ ID NO: 40: (i)SEQUENCE CHARACTERISTICS: (A) LENGTH: 10 amino acids (B) TYPE: aminoacid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (D)OTHER INFORMATION: /note= “Xaa at 1 is (N-Ac-D-Nal(2)); Xaa at 2 is(D-p-Cl-Phe); Xaa at 3 is (D-Trp); Xaa at 6 is (D-L-Arg-Et2); Xaa at 10is (D-Ala-NH2)” (xi) SEQUENCE DESCRIPTION: SEQ ID NO: 40: Xaa Xaa XaaSer His Xaa Trp Lys Pro Xaa 1 5 10 (2) INFORMATION FOR SEQ ID NO: 41:(i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 10 amino acids (B) TYPE: aminoacid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: peptide (ix) FEATURE: (D)OTHER INFORMATION:/note= “Xaa at 1 is (N-Ac-D-Nal(2)); Xaa at 2 is(D-p-Cl-Phe); Xaa at 3 is (D-3- Pal); Xaa at 6 is (D-Arg); Xaa at 7 is(D-Trp); Xaa at 10 is (D-Ala-NH2)” (xi) SEQUENCE DESCRIPTION: SEQ ID NO:41: Xaa Xaa Xaa Ser His Xaa Xaa Lys Pro Xaa 1 5 10

What is claimed:
 1. A method of altering the level of secretion of FSHin a vertebrate animal, comprising administering to the animal aneffective amount of a peptide selected from the group consisting of anl-LHRH-III agonist peptide; an l-LHRH-III superagonist peptide; anl-LHRH-III antagonist peptide; a peptide selected from the groupconsisting of SEQ. ID NO. 6 through SEQ. ID NO. 41; and l-LHRH-III (SEQ.ID NO. 1); wherein the amount of the peptide administered causes aselective change in the serum FSH level of the animal, but does notcause a proportional change in the serum LH level of the animal.
 2. Amethod as recited in claim 1, wherein the level of secretion of FSH inthe animal is increased; said method comprising administering to theanimal an effective amount of l-LHRH-III (SEQ. ID No. 1).
 3. A method asrecited in claim 2, wherein the animal is a mammal.
 4. A method asrecited in claim 3, wherein the animal is a human.
 5. A method asrecited in claim 4, wherein the human is male.
 6. A method as recited inclaim 4, wherein the human is female.
 7. A method of increasing thefertility of a vertebrate animal, comprising increasing the level of FSHsecretion in the animal by the method of claim
 2. 8. A method as recitedin claim 7, wherein the animal is a mammal.
 9. A method as recited inclaim 8, wherein the animal is a human.
 10. A method as recited in claim9, wherein the human is male.
 11. A method as recited in claim 9,wherein the human is female.
 12. A method as recited in claim 1, whereinthe level of secretion of FSH in the animal is increased; said methodcomprising administering to the animal an effective amount of anl-LHRH-III agonist peptide or l-LHRH-III superagonist peptide; whereinthe amount of the peptide administered causes a selective increase inthe serum FSH level of the animal, but does not cause a proportionalincrease in the serum LH level of the animal.
 13. A method as recited inclaim 12, wherein the peptide is selected from the group consisting ofdecapeptides whose sequences are identical to the sequence of l-LHRH-III(SEQ. ID NO. 1), except that either or both of the following conditionsis satisfied: (a) the sixth amino acid residue is a natural orxenobiotic amino acid residue other than aspartic acid; or (b) the ninthamino acid residue is prolyl ethyl amide (ProNHEt); and the tenth aminoacid residue of l-LHRH-III is deleted.
 14. A method as recited in claim13, wherein the peptide is selected from the group consisting of SEQ. IDNO. 6 through SEQ. ID NO.
 32. 15. A method as recited in claim 12,wherein the animal is a mammal.
 16. A method as recited in claim 15,wherein the animal is a human.
 17. A method as recited in claim 16,wherein the human is male.
 18. A method as recited in claim 16, whereinthe human is female.
 19. A method of increasing the fertility of avertebrate animal, comprising increasing the level of FSH secretion inthe animal by the method of claim
 12. 20. A method as recited in claim19, wherein the peptide is selected from the group consisting ofdecapeptides whose sequences are identical to the sequence of l-LHRH-III(SEQ. ID NO. 1), except that either or both of the following conditionsis satisfied: (a) the sixth amino acid residue is a natural orxenobiotic amino acid residue other than aspartic acid; or (b) the ninthamino acid residue is prolyl ethyl amide (ProNHEt); and the tenth aminoacid residue of l-LHRH-III is deleted.
 21. A method as recited in claim20, wherein the peptide is selected from the group consisting of SEQ. IDNO. 6 through SEQ. ID NO.
 32. 22. A method as recited in claim 19,wherein the animal is a mammal.
 23. A method as recited in claim 19,wherein the animal is a human.
 24. A method as recited in claim 23,wherein the human is male.
 25. A method as recited in claim 23, whereinthe human is female.
 26. A method as recited in claim 1, wherein thelevel of secretion of FSH in the animal is decreased; said methodcomprising administering to the animal an effective amount of anl-LHRH-III antagonist peptide; wherein the amount of the peptideadministered causes a selective decrease in the serum FSH level of theanimal, but does not cause a proportional decrease in the serum LH levelof the animal.
 27. A method as recited in claim 26, wherein theantagonist is selected from the group consisting of SEQ. ID NO. 33through SEQ. ID NO.
 41. 28. A method as recited in claim 26, wherein theanimal is a mammal.
 29. A method as recited in claim 28, wherein theanimal is a human.
 30. A method as recited in claim 29, wherein thehuman is male.
 31. A method as recited in claim 29, wherein the human isfemale.
 32. A method of decreasing the fertility of a vertebrate animal,comprising decreasing the level of FSH secretion in the animal by themethod of claim
 26. 33. A method as recited in claim 32, wherein theantagonist is selected from the group consisting of SEQ. ID NO. 33through SEQ. ID NO.
 41. 34. A method as recited in claim 32, wherein theanimal is a mammal.
 35. A method as recited in claim 34, wherein theanimal is a human.
 36. A method as recited in claim 35, wherein thehuman is male.
 37. A method as recited in claim 35, wherein the human isfemale.
 38. A composition selected from the group consisting of anl-LHRH-III agonist peptide; an l-LHRH-III superagonist peptide; anI-LHRH-III antagonist peptide; a peptide selected from the groupconsisting of SEQ. ID NO. 6 through SEQ. ID NO. 41; and an effectiveamount of substantially pure l-LHRH-III (SEQ. ID NO. 1) admixed with apharmaceutically acceptable carrier; wherein said composition has theproperty that said composition will, when administered in an effectiveamount to a vertebrate animal, cause a selective change in the serum FSHlevel of the animal, but will not cause a proportional change in theserum LH level of the animal.
 39. A composition as recited in claim 38,wherein said composition comprises an effective amount of substantiallypure l-LHRH-III (SEQ. ID NO. 1) admixed with a pharmaceuticallyacceptable carrier.
 40. A composition as recited in claim 38, whereinsaid composition comprises a peptide selected from the group consistingof SEQ. ID NO. 6 through SEQ. ID NO.
 32. 41. A peptide as recited inclaim 40, wherein said peptide is SEQ. ID NO.
 6. 42. A peptide asrecited in claim 40, wherein said peptide is SEQ. ID NO.
 7. 43. Apeptide as recited in claim 40, wherein said peptide is SEQ. ID NO. 8.44. A peptide as recited in claim 40, wherein said peptide is SEQ. IDNO.
 9. 45. A peptide as recited in claim 40, wherein said peptide isSEQ. ID NO.
 10. 46. A peptide as recited in claim 40, wherein saidpeptide is SEQ. ID NO.
 11. 47. A peptide as recited in claim 40, whereinsaid peptide is SEQ. ID NO.
 12. 48. A peptide as recited in claim 40,wherein said peptide is SEQ. ID NO.
 13. 49. A peptide as recited inclaim 40, wherein said peptide is SEQ. ID NO.
 14. 50. A peptide asrecited in claim 40, wherein said peptide is SEQ. ID NO.
 15. 51. Apeptide as recited in claim 40, wherein said peptide is SEQ. ID NO. 16.52. A peptide as recited in claim 40, wherein said peptide is SEQ. IDNO.
 17. 53. A peptide as recited in claim 40, wherein said peptide isSEQ. ID NO.
 18. 54. A peptide as recited in claim 40, wherein saidpeptide is SEQ. ID NO.
 19. 55. A peptide as recited in claim 40, whereinsaid peptide is SEQ. ID NO.
 20. 56. A peptide as recited in claim 40,wherein said peptide is SEQ. ID NO.
 21. 57. A peptide as recited inclaim 40, wherein said peptide is SEQ. ID NO.
 22. 58. A peptide asrecited in claim 40, wherein said peptide is SEQ. ID NO.
 23. 59. Apeptide as recited in claim 40, wherein said peptide is SEQ. ID NO. 24.\60. A peptide as recited in claim 40, wherein said peptide is SEQ. IDNO.
 25. 61. A peptide as recited in claim 40, wherein said peptide isSEQ. ID NO.
 26. 62. A peptide as recited in claim 40, wherein saidpeptide is SEQ. ID NO.
 27. 63. A peptide as recited in claim 40, whereinsaid peptide is SEQ. ID NO.
 28. 64. A peptide as recited in claim 40,wherein said peptide is SEQ. ID NO.
 29. 65. A peptide as recited inclaim 40, wherein said peptide is SEQ. ID NO.
 30. 66. A peptide asrecited in claim 40, wherein said peptide is SEQ. ID NO.
 31. 67. Apeptide as recited in claim 40, wherein said peptide is SEQ. ID NO. 32.68. A composition as recited in claim 38, wherein said compositioncomprises a peptide selected from the group consisting of SEQ. ID NO. 33through SEQ. ID NO.
 41. 69. A peptide as recited in claim 68, whereinsaid peptide is SEQ. ID NO.
 33. 70. A peptide as recited in claim 68,wherein said peptide is SEQ. ID NO.
 34. 71. A peptide as recited inclaim 68, wherein said peptide is SEQ. ID NO.
 35. 72. A peptide asrecited in claim 68, wherein said peptide is SEQ. ID NO.
 36. 73. Apeptide as recited in claim 68, wherein said peptide is SEQ. ID NO. 37.74. A peptide as recited in claim 68, wherein said peptide is SEQ. IDNO.
 38. 75. A peptide as recited in claim 68, wherein said peptide isSEQ. ID NO.
 39. 76. A peptide as recited in claim 68, wherein saidpeptide is SEQ. ID NO.
 40. 77. A peptide as recited in claim 68, whereinsaid peptide is SEQ. ID NO. 41.